in Windows, pulling from repo that has symlinks results in ErrUnstagedChanges

[808codist]

Steps to reproduce:

1. Create a repo with symlinks on github (or other git repo host)
2. On Windows machine, use _examples/clone/main.go to clone the repo
   • I ran as Administrator
   • I modified source to set CloneOptions.Auth
3. Without using clone from previous step, push a new commit to the repo
4. Back on Windows machine, use _examples/pull/main.go to pull just-pushed commit
   • I ran as Administrator
   • I modified source to set PullOptions.Auth
5. Notice worktree contains unstaged changes error message

Seems to be Windows-specific, since I could not reproduce on Linux (CentOS), with same modified source.

details:

• go version go1.10 windows/amd64
• Windows 10 Version 1709 (OS Build 16299.309)
• gopkg.in/src-d/go-git.v4

[808codist]

Better way to reproduce the bug, go run this code on a Windows box:

package main

import (
	"io/ioutil"
	"os"

	"golang.org/x/crypto/ssh"
	"gopkg.in/src-d/go-git.v4"
	"gopkg.in/src-d/go-git.v4/_examples"
	"gopkg.in/src-d/go-git.v4/plumbing/transport"
	go_git_ssh "gopkg.in/src-d/go-git.v4/plumbing/transport/ssh"
	"fmt"
)

const privateSshKeyFile = "C:/full/path/private/key/file"
const url = "git@github.com:808codist/go-git-symlink-test.git"

func main() {
	examples.CheckArgs("<directory>")
	directory := os.Args[1]

	r, err := git.PlainClone(directory, false, &git.CloneOptions{
		URL:               url,
		RecurseSubmodules: git.DefaultSubmoduleRecursionDepth,
		Auth:              getAuth(),
	})
	examples.CheckIfError(err)

	w, err := r.Worktree()
	examples.CheckIfError(err)

	status, err := w.Status()
	examples.CheckIfError(err)
	if len(status) > 0 {
		fmt.Println("Changes exist!:\n", status)
	} else {
		fmt.Println("No changes - yay!!!!!")
	}
}

func getAuth() transport.AuthMethod {
	var auth transport.AuthMethod
	sshKey, err := ioutil.ReadFile(privateSshKeyFile)
	examples.CheckIfError(err)
	signer, err := ssh.ParsePrivateKey([]byte(sshKey))
	examples.CheckIfError(err)
	auth = &go_git_ssh.PublicKeys{User: "git", Signer: signer}
	return auth
}

[808codist]

Note that git status on the local clone returns "nothing to commit, working tree clean"